Earthquake · reviewed by a seismologist
M 1.8ml
Earthquake near Dillon, MT
No earthquake was likely felt in Dillon in the 24 hours to 9:51 am MST (16:51 UTC). The last one was M 2.0, 14 km (9 mi) N, at 2:45 pm MDT on 7 May 2026, estimated intensity II (weak) in town. Every earthquake near Dillon
This page: a magnitude 1.8 earthquake was recorded 39 km (24 mi) northeast of Dillon, MT, at 4:01 am MDT on 5 April 2021 (10:01 UTC), 10 km deep.
USGS: 7 km W of Sheridan, Montana
- When
- 4:01 am MDT on 5 April 2021 ()
- Where
- 39 km (24 mi) northeast of Dillon, MT · earthquakes near Dillon
- Montana today
- every earthquake in Montana in the last 24 hours
- Magnitude
- M 1.8 (ml)
- Depth
- 10 km below the surface
- Felt
- no reports yet
- Nearest
- Madison County, 33 km ESE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2046 days ago
Earthquake alerts for Dillon, MT
Get a notification in this browser when USGS records an earthquake near Dillon, MT. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 8 km (5 mi) from the epicentre. In Dillon, 39 km away, the estimate is intensity I (not felt). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.
How big was it?
This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 790,000× the energy of this one
- Around the size people start to feel M 3.0 70× the energy of this one
- This earthquake M 1.8 about 14 lb of TNT
Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.
For this area
The largest earthquake within 50 km since 2016 was M 4.0 on 2016-09-03 — about 2,500 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.6 16 km N of Dillon, Montana · 27 km WSW of this epicentre
Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.
Where
Epicentre 45.4638, -112.2925. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Madison County, MT | 33 km (21 mi) | ESE | earthquakes near Madison County |
| Silver Bow County, MT | 56 km (35 mi) | NNW | earthquakes near Silver Bow County |
| Beaverhead County, MT | 60 km (37 mi) | SW | earthquakes near Beaverhead County |
| Jefferson County, MT | 76 km (47 mi) | NNE | earthquakes near Jefferson County |
| Gallatin County, MT | 88 km (55 mi) | E | earthquakes near Gallatin County |
| Deer Lodge County, MT | 96 km (60 mi) | NW | earthquakes near Deer Lodge County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
52 earthquakes have been recorded within 50 km since this one.
- 2.3 12 km N of Dillon, Montana
- 2.0 Western Montana
- 1.6 18 km WNW of Pony, Montana
- 1.8 3 km NNW of Alder, Montana
- 2.5 13 km NNW of Ennis, Montana
- 1.9 17 km N of Dillon, Montana
- 1.9 12 km NNW of Ennis, Montana
- 1.9 8 km ESE of Sheridan, Montana
- 1.8 14 km N of Dillon, Montana
- 1.7 17 km S of Pony, Montana
- 2.2 20 km W of Pony, Montana
- 2.3 13 km NNE of Dillon, Montana
- 1.5 3 km ESE of Twin Bridges, Montana
- 1.6 7 km N of Twin Bridges, Montana
- 1.5 8 km S of Harrison, Montana
Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.
On USGS
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.